In this art of mining, a plurality of cutting bits are attached to a rotating drum and advanced into a wall of rock to be mined. In a typical arrangement, the bit is held in a block which is mounted to the drum in a fixed position. Adjacent blocks are oriented with respect to each other so that each bit cuts a clearance for a succeeding bit. The bits are heated by frictional engagement with the rock, and dust is created by the cutting operation. Accordingly, it is known to provide a channel within the bit and supply that channel with a pressurized fluid, such as water, to cool the bit and reduce dust.
U.S. Pat. Nos. 3,397,012 (Krekeler) and 3,512,838 (Kniff) show mining tools wherein a conical bit having a cylindrical shank is held in a cylindrical opening in a holder. U.S. Pat. No. 4,193,638 (Heckenhauer) shows a multiple tip mining arrangement wherein a drum has a plurality of cutting bits mounted to an exterior surface. Each bit is held in a holder, and the shank of the bit is received in a tapered socket which is multi-sided to allow the bit to be indexed. U.S. Pat. Nos. 4,488,758 (Clemmow et al.) and 4,529,250 (Radford et al.) show a mining bit wherein a channel carries fluid through the bit to a spray opening. U.S. Pat. No. 4,453,775 (Clemmow) shows a cutting tool having a hardened cutting insert.